The present invention relates to a novel triketone derivative and a herbicide containing the triketone derivative as an active ingredient. More particularly, the invention relates to a triketone derivative useful for a herbicide effective on weeds which inhibit growth of crop plants, enter alia, for paddy field weeds such as Echinochloa crus-galli and Scirups juncoides, and to a herbicide containing the triketone derivative as an active ingredient.
Herbicides are important chemicals for facilitating weed control and enhancing productivity of field and garden crops. Therefore, development of herbicides which is safe and has excellent weed-controlling property even at a low dose have been actively carried out for many years.
There is proposed a herbicide containing a triketone derivative having a bicyclic benzoyl structure as an active ingredient, for the herbicide has excellent safety to field crops and excellent weed-controlling activity to field weeds. For example, there is proposed a herbicide containing a compound disclosed in Japanese Patent No. 2579663 and International Patent Publication WO97/08164 as an active ingredient, which herbicide has an excellent weed-controlling property suitable for growth of field crops. However, a herbicide containing such a compound as an active ingredient has poor activity for controlling paddy field weeds, and disadvantageously has insufficient safety to a paddy rice plant.
In view of the foregoing, an object of the present invention is to provide a herbicide containing a triketone derivative as an active ingredient, which herbicide can control a wide range of weeds at a low dose and imparts a low level of chemical injury to cultivated crops, particularly a paddy rice plant.
In order to attain the above object, the present inventors have conducted earnest studies, and have found that a triketone derivative having a specific chemical structure can control a wide range of weeds at a low dose and imparts a low level of chemical injury to cultivated crops. The present invention has accomplished based on this finding.
The present invention includes first and second aspects as described below.
The first aspect of the present invention encompasses the following.
(1) A triketone derivative represented by formula [I-1]: 
xe2x80x83wherein R represents a methyl group; each of X and Y represents a hydrogen atom, a halogen atom, a nitro group, an amino group, a cyano group, a hydroxy group, a mercapto group, xe2x80x94R1, xe2x80x94OR1, xe2x80x94SR1, xe2x80x94SO2R1, xe2x80x94NR2R3, or xe2x80x94NHCOR1, wherein R1 represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted; each of R2 and R3 represents a hydrogen atom, a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted, or R2 and R3 may be bonded to each other to form a group having a cyclic structure; M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an organic base; R4 represents a hydrogen atom or a C1-C6 alkyl group; and m is an integer between 0 and 4 inclusive; provided that not all of X, Y, and R4 simultaneously represent methyl groups.
(2) A triketone derivative represented by formula [I-2]: 
xe2x80x83wherein R, X, Y, M, and m have the same definitions as described in relation to formula [I-1].
xe2x80x83(3) A triketone derivative represented by formula [I-3]: 
xe2x80x83wherein R, X, M, R4, and m have the same definitions as described in relation to formula [I-1].
(4) A triketone derivative represented by formula [1-4): 
xe2x80x83wherein R represents a methyl group; each of X and Y represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, xe2x80x94R1, xe2x80x94OR1, xe2x80x94SR1, or xe2x80x94NR2R3, wherein R1 represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted; each of R2 and R3 represents a hydrogen atom, a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted, or R2 and R3 may be bonded to each other to form a group having a cyclic structure; Z represents xe2x80x94OR1, xe2x80x94SOpR1, xe2x80x94A(CH2)nQR1, xe2x80x94NR2R3, xe2x80x94N(OR1)R2, xe2x80x94O(Cxe2x95x90O)R1, xe2x80x94O(Cxe2x95x90O)OR1, xe2x80x94O(Cxe2x95x90O)SR1, xe2x80x94O(Cxe2x95x90O)NR2R3, or xe2x80x94O(Cxe2x95x90S)NR2R3 (wherein R1, R2, and R3 have the same definitions as described in relation to X and Y, each of A and Q represents an oxygen atom or a sulfur atom, p is 0, 1, or 2, n is 1 or 2), xe2x80x94OM (wherein M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an organic base), or a halogen atom; and m is an integer between 0 and 4 inclusive.
(5) A triketone derivative according to (4), wherein Z represents an xe2x80x94OM group (wherein M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an organic base).
(6) A triketone derivative according to any one of (1), (2), (4), and (5), wherein Y represents a hydrogen atom, a C1-C6 alkyl group, or a halogen atom.
(7) A triketone derivative according to any one of (1), (2), (4), and (5), wherein Y represents a hydrogen atom or a methyl group.
(8) A triketone derivative according to any one of (2), (4), and (5), wherein Y represents a hydrogen atom.
(9) A triketone derivative according to any one of (1) to (8), wherein X represents xe2x80x94R1, xe2x80x94OR1, or xe2x80x94SR1.
(10) A triketone derivative according to (1) or (9), wherein X represents a halogen atom or a methyl group.
(11) A triketone derivative according to any one of (1) to
(10), wherein M represents a hydrogen atom.
(12) A herbicide containing a triketone derivative as recited in any one of (1) to (11) as an active ingredient.
(13) A herbicide for use in cultivation of a paddy rice plant, which herbicide contains a triketone derivative as recited in any one of (1) to (11) as an active, ingredient.
The second aspect of the present invention encompasses the following.
(1) A triketone derivative represented by formula [II-1]: 
xe2x80x83wherein R represents a methyl group; X represents a hydrogen atom, a halogen atom, a nitro group, an amino group, a cyano group, a hydroxy group, a mercapto group, xe2x80x94R1, xe2x80x94OR1, xe2x80x94SR1, xe2x80x94SO2R1, xe2x80x94NR2R3, or xe2x80x94NHCOR1 (wherein R1 represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted; each of R2 and R3 represents a hydrogen atom, a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted, or R2 and R3 may be bonded to each other to form a group having a cyclic structure);
G contains 3 to 5 ring-constituting atoms which form a 5- to 7-membered saturated or unsaturated condensed ring including two carbon atoms of the benzene ring adjacent to G, wherein two or less ring-constituting atoms are selected from among nitrogen, oxygen, and sulfur, and the ring-constituting atoms may have one or more substituents selected from among a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a hydroxy group, a mercapto group, an oxo group, a thioxo group, a hydroxyimino group, a C1-C6 alkoxyimino group, a hydrazono group, a C1-C6 monoalkylhydrazono group, and a C1-C6 dialkylhydrazono group, and a carbon atom or the adjacent carbon atom of the ring-constituting atom may have a substituent selected from among an ethylenedioxy group, an ethylenedithio group, a propylenedioxy group, and a propylenedithio group, with these substituents optionally being substituted with a halogen atom or a C1-C6 alkyl group;
Z1 represents a halogen atom, xe2x80x94OR1, xe2x80x94SOpR1, xe2x80x94A(CH2)nQR1, xe2x80x94NR2R3, xe2x80x94N(OR1)R2, xe2x80x94O(Cxe2x95x90O)R1, xe2x80x94O(Cxe2x95x90O)OR1, xe2x80x94O(Cxe2x95x90O)SR1, xe2x80x94O(Cxe2x95x90O)NR2R3, or xe2x80x94O(Cxe2x95x90S)NR2R3 (wherein R1, R2, and R3 have the same definitions as described in relation to X, each of A and Q represents an oxygen atom or a sulfur atom, p is 0, 1, or 2, n is 1 to 3), or a halogen atom; m is an integer between 0 and 4 inclusive; and q is 1 or 2.
(2) A triketone derivative according to (1), which is represented by formula [II-2] or [II-3]: 
xe2x80x83wherein R, X, G, Z1, m, and q have the same definitions as described in relation to formula [II-1].
(3) A triketone derivative according to (1) or (2), which is represented by any one of formulas [II-4] to [II-9]: 
xe2x80x83wherein R, X, G, Z1, m, and q have the same definitions as described in relation to formula [II-1], each of G1 to G4 represents an optionally substituted atom that constitutes G in formula [II-1], and i is 0, 1, or 2.
(4) A triketone derivative according to any one of (1) to (3), wherein X represents a halogen atom, xe2x80x94R1, xe2x80x94OR1, or xe2x80x94SR1.
(5) A triketone derivative according to (3) or (4), wherein each of G1 to G4 represents a ring-constituting atom having one or more substituents selected from the substituent group consisting of an unsubstituted or C1-C6 alkyl group, a C1-C6 alkoxy group, an oxo group, and a C1-C6 alkoxyimino group.
(6) A triketone derivative according to any one of (1) to (5), wherein Z1 is selected from among a halogen atom, xe2x80x94OR1, xe2x80x94SOpRl, xe2x80x94A(CH2)nQR1, and xe2x80x94N(OR1)R2.
(7) A triketone derivative represented by formula [II-10]: 
xe2x80x83wherein R represents a methyl group; each of X and Y represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, xe2x80x94R1, xe2x80x94OR1, xe2x80x94SR1, or xe2x80x94NR2R3 (wherein R1 represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted, each of R2 and R3 represents a hydrogen atom, a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, a phenyl group which may be substituted, or a benzyl group which may be substituted, or R2 and R3 may be bonded to each other to form a group having a cyclic structure); Z represents xe2x80x94OR1, xe2x80x94SOpR1, xe2x80x94A(CH2)nQR1, xe2x80x94NR2R3, xe2x80x94N(OR1)R2, xe2x80x94O(Cxe2x95x90O)R1, xe2x80x94O(Cxe2x95x90O)OR1, xe2x80x94O(Cxe2x95x90O)SR1, xe2x80x94O(Cxe2x95x90O)NR2R3, or xe2x80x94O(Cxe2x95x90S)NR2R3 (wherein R1, R2, and R3 have the same definitions as described in relation to X and Y, each of A and Q represents an oxygen atom or a sulfur atom, p is 0, 1, or 2, n is 1 or 2), xe2x80x94OM (wherein M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an organic base), or a halogen atom; and m is an integer between 0 and 4 inclusive.
(8) A triketone derivative according to (7), wherein Y represents a hydrogen atom or a methyl group.
(9) A triketone derivative according to (7), wherein Y represents a hydrogen atom.
(10) A triketone derivative according to any one of (7) to (9), wherein Z represents a halogen atom, xe2x80x94OR1, xe2x80x94SOpR1, xe2x80x94A(CH2)nQR1, or xe2x80x94N(OR1)R2.
(11) A triketone derivative according to any one of (1) to
(10), wherein X represents a halogen atom or a methyl group.
(12) A herbicide containing a triketone derivative as recited in any one of (1) to (11) as an active ingredient.
(13) A herbicide for use in cultivation of a paddy rice plant, which herbicide contains a triketone derivative as recited in any one of (1) to (11) as an active ingredient.
Hereafter, various modes for carrying out the present invention will be described.
The triketone derivative of the first aspect of the present invention (may be simply referred to as xe2x80x9cthe present inventionxe2x80x9d throughout section I) is represented by chemical formula [I-1]. Of these, triketone derivatives represented by formulas [I-2] and [I-3] are preferred in that they provide a low level of chemical injury to cultivated plants and have an excellent weed-controlling effect.
When each of R1 to R3 in formulas [I-1] to [I-4] represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an i-pentyl group, a sec-pentyl group, an n-hexyl group, and an i-hexyl group. The ethyl group, propyl groups, and butyl groups may have an unsaturated bond, and the propyl groups, butyl groups, pentyl groups, and hexyl groups may be linear, branched, or cyclic. Of these, a methyl group and an ethyl group are preferred.
When each of R1 to R3 in formulas (I-1] to [I-4] represents a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, examples of the haloalkyl group include the above-described alkyl groups in which some or all of the hydrogen atoms are substituted by a halogen atom such as a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom. Specific examples include a chloromethyl group, a difluoromethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-chloroethyl group, a 2-fluoroethyl group, a 3-chloropropyl group, and a 3-fluoropropyl group. Of these, a trifluoromethyl group and a trichloromethyl group are preferred.
When each of R1 to R3 in formulas [I-1] to [I-4] represents a phenyl group which may be substituted, examples of the phenyl group include a phenyl group, a tolyl group, an m-chlorophenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, and p-cyanophenyl group. When each of R1 to R3 represents a benzyl group which may be substituted, examples of the benzyl group include a benzyl group, an xcex1-methylbenzyl group, an o-methylbenzyl group, an m-chlorobenzyl group, a p-methoxybenzyl group, a p-nitrobenzyl group, and a p-cyanobenzyl group.
When each of X and Y in formulas [I-1] to [I-4] or Z in formula [I-4] represents an xe2x80x94OR1, examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an i-pentyloxy group, a sec-pentyloxy group, an n-hexyloxy group, and an i-hexyloxy group. The propoxy groups and butoxy groups may have an unsaturated bond and may be linear, branched, or cyclic. In the above-described alkoxy groups, some or all of the hydrogen atoms may be substituted by a halogen atom. Examples of such haloalkoxy groups include a chloromethyloxy group, a difluoromethyloxy group, a trichloromethyloxy group, a trifluoromethyloxy group, a 2-chloroethyloxy group, a 2-fluoroethyloxy group, a 3-chloropropyloxy group, and a 3-fluoropropyloxy group. Of these, a methoxy group, an ethoxy group, a difluoromethyloxy group, and a trifluoromethyloxy group are preferred.
When each of X and Y in formulas [I-1] to [I-4] represents an xe2x80x94SR1 group, examples of the alkylthio group include a methylthio group, an ethylthio group, an n-propylthio group, an i-propylthio group, an n-butylthio group, an i-butylthio group, a sec-butylthio group, a tert-butylthio group, an n-pentylthio group, an i-pentylthio group, an n-hexylthio group, and an i-hexylthio group. The propylthio groups and butylthio groups may have an unsaturated bond and may be linear, branched, or cyclic. In the above-described alkylthio groups, some or all of the hydrogen atoms may be substituted by a halogen atom. Examples of such haloalkylthio groups include a chloromethylthio group, a difluoromethylthio group, a trichloromethylthio group, a trifluoromethylthio group, a 2-chloroethylthio group, a 2-fluoroethylthio group, a 3-chloropropylthio group, and a 3-fluoropropylthio group. Of these, a methylthio group, an ethylthio group, and a trifluoromethylthio group are preferred.
Examples of the xe2x80x94SO2R1 group include a methylsulfonyl group, an ethylsulfonyl group, an n-propylsulfonyl group, an i-propylsulfonyl group, an n-butylsulfonyl group, an i-butylsulfonyl group, a sec-butylsulfonyl group, and a tert-butylsulfonyl group. Of these, a methylsulfonyl group and an ethylsulfonyl group are preferred.
When each of X, Y, and Z in formulas [I-1] to [I-4] represents an xe2x80x94NR2R3 group, examples thereof include a methylamino group, a dimethylamino group, an ethylamino group, a pyrrolidinyl group, and a piperidino group. Examples of the xe2x80x94N(OR1)R2 group include a methoxyamino group, a methoxymethylamino group, a benzyloxyamino group, and an allyloxyamino group.
Example of the xe2x80x94NHCOR1 include xe2x80x94NHCOCH3, xe2x80x94NHCOC2H5, xe2x80x94NHCOC3H7, and xe2x80x94NHCOC4H10.
R4 in formulas [I-1] and [1-3] represents a hydrogen atom or a C1-C6 alkyl group. Examples of the C1-C6 alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an i-pentyl group, a sec-pentyl group, an n-hexyl group, and an i-hexyl group. Of these, a hydrogen atom and a methyl group are preferred, with a hydrogen atom being particularly preferred.
Examples of preferable X in formulas [I-1] to [I-4] include a halogen atom, xe2x80x94R1, xe2x80x94OR1, and xe2x80x94SR1, with a halogen atom and a methyl group being particularly preferred. Examples of preferable Y in formulas [I-1] to [I-4] include a hydrogen atom, a halogen atom, and xe2x80x94R1, with a hydrogen atom, a methyl group, and a fluorine atom being particularly preferred.
The number xe2x80x9cmxe2x80x9d in formulas [I-1] to [I-4] is 0-4, preferably 0-2, particularly preferably 0.
When Z in formula [I-4] represents an xe2x80x94SOPR1 group, examples thereof include alkylsulfonyl groups such as a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, a butylsulfonyl group, a pentylsulfonyl group, and a hexylsulfonyl group; alkylsulfinyl groups such as a methylsulfinyl group, an ethylsulfinyl group, a propylsulfinyl group, a butylsulfinyl group, a pentylsulfinyl group, and a hexylsulfinyl group; and alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, and a hexylthio group.
Examples of M contained in the xe2x80x94OM group in formulas [I-1] to [I-3] and in formula [I-4] when Z represents an xe2x80x94OM group include a hydrogen atom; alkali metal atoms such as lithium, sodium, and potassium; alkaline earth metal atoms such as magnesium, calcium, and barium; organic bases such as trimethylamine, triethylamine, and aniline. Of these, a hydrogen atom is particularly preferred as M.
When Z in a triketone derivative represented by formula [I-4] is a hydroxy group, the derivative may be tautomers having the following structures: 
wherein R, R4, X, Y, and m have the same definitions as described in relation to formula [I-4]. The triketone derivative of the present invention encompasses all these tautomeric compounds and mixtures thereof.
A process for producing the triketone derivative of the present invention will next be described. First of all, an intermediate for producing the triketone derivative of the present invention; i.e., benzothiophene-2-carboxylic acid, is produced. For example, the intermediate can be effectively produced through the following steps.
(1) First Step 
In the first step, Compounds (a) and (b) are used in an amount of 1 mol each to carry out the above reaction in the presence of 1 mol or more of a base to thereby obtain Compound (c). Either of Compound (a) or Compound (b) may be used in an amount in excess of equimol with respect to the other.
Examples of the base which can be used in the reaction include an alkali metal carbonate, an alkaline earth metal carbonate, and an alkali metal hydroxide. Examples of a solvent which is inert to the reaction and used in the reaction include alcohols such as methanol and ethanol; halohydrocarbons such as chloroform and dichloromethane; hydrocarbons such as hexane and toluene; N,N-dimethylformamide; and water. The reaction is carried out in the temperature range of 0xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of the reaction.
Alternatively, the reaction may be carried out in a two-phase system in the presence of a quaternary ammonium salt. Furthermore, Compound (a) may be reacted with sodium hydrogensulfide or potassium hydrogensulfide, and chloroacetic acid or bromoacetic acid, to thereby obtain Compound (c).
When the substituent X or Y in Compound (c) is a leaving group, the product may be obtained as a mixture. In this case, the product is purified through a process such as distillation, recrystallization, or chromatographic purification, to thereby yield the target compound.
(2) Second Step 
In the second step, Compound (c) is cyclized to form Compound (d) as shown in the above reaction. The cyclization is carried out in the presence of an acidic reagent in a catalyst amount or in an amount of equimol or more. Examples of preferred acidic reagents include hydrochloric acid, sulfuric acid, phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, polyphosphoric acid, acetic acid, acetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, and sulfuryl chloride. The reaction may be carried out in the absence of a solvent. When a solvent is employed, examples of preferred solvents include hexane, dichloromethane, 1,2-dichloroethane, chloroform, and N,N-dimethylformamide. The reaction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of the reaction.
Alternatively, Compound (c) is transformed into its acid halide, and the acid halide is reacted in the presence of a Lewis acid. In this case, the transformation is carried out by use of a halogenating agent such as oxalyl chloride or thionyl chloride in an amount of equimol or more in the absence of a solvent or in the presence of a solvent such as methylene chloride, 1,2-dichloroethane, or chloroform. The reaction is carried out in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction. The subsequent reaction is carried out by use of a Lewis acid such as aluminum chloride, titanium tetrachloride, or tin tetrachloride. The reaction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of the reaction. When Y of Compound (d) is a hydrogen atom, the other isomer may be intermingled with the product as an impurity. In such a case, the product is purified through a method as described above.
(3) Third Step 
In the third step, Compound (d) is reduced to form Compound (e) as shown in the above reaction. Examples of preferred reducing agents used in the reduction include sodium borohydride and aluminum triisopropoxide. Examples of preferred solvents include methanol, ethanol, water, dichloromethane, and toluene. The reduction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of an employed solvent, with stirring until completion of the reaction.
(4) Fourth Step 
In the fourth step, Compound (e) is dehydrated to form Compound (f) as shown in the above reaction. The dehydration may be carried out in the presence of a catalyst amount of an acidic substance such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, or Amberlist. In this case, a solvent such as benzene or toluene is preferred as a reaction solvent, in that water formed during dehydration can be removed through azeotropic distillation. The formed water is adsorbed in an adsorbent such as a molecular sieve, or is removed through azeotropic distillation with the solvent, to thereby accelerate dehydration. When such an adsorbent is used, the dehydration is carried out in the temperature range of room temperature to 50xc2x0 C. with stirring until completion of the reaction. Azeotropic distillation is carried out through refluxing with heat at the boiling point of the employed solvent until the theoretical amount of water is removed.
(5) Fifth Step 
In the fifth step, Compound (f) is oxidized to form Compound (g) as shown in the above reaction. The oxidation is carried out in the presence of an organic peroxide such as hydrogen peroxide or m-chloroperbenzoic acid in an amount of 2 mol or more. In this case, a solvent such as acetic acid or methylene chloride is preferred as a reaction solvent. The oxidation is carried out in the temperature range of xe2x88x9220xc2x0 C. to 100xc2x0 C., with stirring until completion of the reaction.
(6) Sixth Step 
In the sixth step, Compound (g) is hydrogenated to form Compound (h) as shown in the above reaction. The hydrogenation is carried out under similar conditions as employed for customary catalytic hydrogenation. Examples of preferred catalysts include palladium-on-active carbon, Raney nickel, and platinum oxide. In this case, a solvent such as tetrahydrofuran, methanol, ethanol, ethyl acetate, or water is preferred as a reaction solvent. The hydrogenation is carried out in a hydrogen gas atmosphere, with or without pressure, and in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction.
(7) Seventh Step 
In the seventh step, Compound (h) is hydrolyzed to form Compound (i) as shown in the above reaction. The hydrogenation is carried out in the presence of an alkali metal hydroxide in an amount of equimol or more in a mixture of water and alcohol such as ethanol as a solvent. The hydrolysis is carried out in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction.
The thus-obtained intermediate, benzothiophene-2-carboxylic acid, is used in the following reaction: 
wherein R, R4, X, Y, and m have the same definitions as described in relation to formula [I-1] to [I-4], to thereby produce triketone derivatives as represented by formula [I-1] to [I-3] and a triketone derivative as represented by formula [I-4] wherein Z represents a hydroxy group.
The intermediate, benzothiophene-2-carboxylic acid, is transformed into an acid halide thereof as described in relation to the above-described cyclization. The thus-formed acid halide is reacted with a diketone in the presence of an organic base such as triethylamine at 0-20xc2x0 C. in an inert organic reaction solvent such as acetonitrile, and the reaction mixture is allowed to react with stirring at room temperature in the presence of a catalyst amount of a cyanide-donor such as acetone cyanohydrin.
Furthermore, the thus-obtained triketone derivatives represented by formula [I-1] to [I-3] and triketone derivative represented by formula [I-4] wherein Z represents a hydroxy group are reacted with a compound which can substitute some or all of the hydroxy groups in accordance with reaction, e.g., reaction as described in Japanese Patent Application Laid-Open (kokai) Nos. 62-298563, 62-242755, or 63-2947, to thereby produce substituted triketone derivatives represented by formula [I-1] to [I-3] and triketone derivative represented by formula [I-4] wherein Z represents a variety of substituents.
The triketone derivative of the second aspect of the present invention (may be simply referred to as xe2x80x9cthe present inventionxe2x80x9d throughout section II) is represented by chemical formula [II-1]. Of these, triketone derivatives represented by formulas [II-2] and [II-3] are preferred. Furthermore, among the triketone derivatives represented by formulas [II-2] and [II-3], triketone derivatives represented by formulas [II-4] to [II-9] are more preferred in that they provide a low level of chemical injury to cultivated plants and have an excellent weed-controlling effect.
In the triketone derivatives represented by formulas [II-1] to [II-9], the substituent represented by X is preferably a halogen atom, an alkyl group represented by xe2x80x94R1, an alkoxy group represented by xe2x80x94OR1, or an alkylthio group represented by xe2x80x94SR1. In the triketone derivative represented by formula [II-10], the substituent Y represents a hydrogen atom or a variety of groups. Of these, a hydrogen atom and a methyl group are preferred. In the triketone derivative represented by formula [II-10], the substituent X represents a variety of groups. Of these, a halogen atom and a methyl group are preferred.
In the triketone derivative represented by formulas [II-1] to [II-10], each of the substituents Z and Z1 represents a variety of groups. Of these, a halogen atom, and xe2x80x94OR1, xe2x80x94SOpR1, xe2x80x94A(CH2)QR1, xe2x80x94NR2R31 and xe2x80x94N(OR1)R2 described below are preferred.
When each of R1 to R3 in formulas [II-1] to [II-9] represents a C1-C6 alkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an i-pentyl group, a sec-pentyl group, an n-hexyl group, and an i-hexyl group. The ethyl group, propyl groups, and butyl groups may have an unsaturated bond, and the propyl groups, butyl groups, pentyl groups, and hexyl groups may be linear, branched, or cyclic. Of these, a methyl group and an ethyl group are preferred.
When each of R1 to R3 represents a C1-C6 haloalkyl group which may have a branched structure, a cyclic structure, or an unsaturated bond, examples of the haloalkyl group include the above-described alkyl groups in which some or all of the hydrogen atoms are substituted by a halogen atom such as a chlorine atom, a fluorine atom, a bromine atom, or an iodine atom. Specific examples include a chloromethyl group, a difluoromethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-chloroethyl group, a 2-fluoroethyl group, a 3-chloropropyl group, and a 3-fluoropropyl group. Of these, a trifluoromethyl group is preferred.
When each of R1 to R3 represents a phenyl group which may be substituted, examples of the phenyl group include a phenyl group, a tolyl group, an m-chlorophenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, and p-cyanophenyl group. When each of R1 to R3 represents a benzyl group which may be substituted, examples of the benzyl group include a benzyl group, an xcex1-methylbenzyl group, an o-methylbenzyl group, an m-chlorobenzyl group, a p-methoxybenzyl group, a p-nitrobenzyl group, and a p-cyanobenzyl group. Of these, a phenyl group and a benzyl group are preferred. When each of X, Y, and Z1 in formulas [II-1] to [II-9] represents an xe2x80x94OR1 group, examples of the alkoxy group include a methoxy group, an ethoxy group, propoxy groups, butoxy groups, pentyloxy groups, and hexyloxy groups. The propoxy groups and butoxy groups may have an unsaturated bond and may be linear, branched, or cyclic. In the above-described alkoxy groups, some or all of the hydrogen atoms may be substituted by a halogen atom. Examples of such haloalkoxy groups include a chloromethyloxy group, a difluoromethyloxy group, a trichloromethyloxy group, a trifluoromethyloxy group, a 2-chloroethyloxy group, a 2-fluoroethyloxy group, a 3-chloropropyloxy group, and a 3-fluoropropyloxy group. Of these, a methoxy group, an ethoxy group, and an isopropoxy group are preferred.
When each of X, Y, and Z1 in formulas [II-1] to [II-9] represents an xe2x80x94SR1 group, examples of the alkylthio group include a methylthio group, an ethylthio group, propylthio groups, butylthio groups, pentylthio groups, and hexylthio groups. The propylthio groups and butylthio groups may have an unsaturated bond and may be linear, branched, or cyclic. In the above-described alkylthio groups, some or all of the hydrogen atoms may be substituted by a halogen atom. Examples of such haloalkylthio groups include a chloromethylthio group, a difluoromethylthio group, a trichloromethylthio group, a trifluoromethylthio group, a 2-chloroethylthio group, a 2-fluoroethylthio group, a 3-chloropropylthio group, and a 3-fluoropropylthio group. Of these, a methylthio group, an ethylthio group, an i-propylthio group, and a t-butylthio group are preferred.
When each of X, Y, and Z1 in formulas [II-1] to [II-9] represents an xe2x80x94SOpR1 group, examples of the xe2x80x94SOpR1 group include alkylsulfonyl groups such as a methylsulfonyl group, an ethylsulfonyl group, propylsulfonyl groups, butylsulfonyl groups, pentylsulfonyl groups, and hexylsulfonyl groups; alkylsulfinyl groups such as a methylsulfinyl group, an ethylsulfinyl group, propylsulfinyl groups, butylsulfinyl groups, pentylsulfinyl groups, and hexylsulfinyl groups; and alkylthio groups such as a methylthio group, an ethylthio group, propylthio groups, butylthio groups, pentylthio groups, and hexylthio groups. Of these, a methylsulfonyl group and an ethylsulfonyl group are preferred. In addition, when each of X, Y, and Z1 in the formulas represents an xe2x80x94NR2R3 group, examples thereof include a methylamino group, a dimethylamino group, an ethylamino group, a pyrrolidinyl group, and a piperidino group. When each of X, Y, and Z1 in the formulas represents an xe2x80x94N(OR1)R2 group, examples of the xe2x80x94N(OR1)R2 group include a methoxyamino group, a methoxymethylamino group, a benzyloxyamino group, and an allyloxyamino group. Of these, a methoxymethylamino group is preferred.
The number xe2x80x9cq,xe2x80x9d the number of the substituent X, is 1 or 2, with 1 being preferred.
When Z in formula [II-10] represents an xe2x80x94O(Cxe2x95x90O)R1 group, examples include an acetoxy group and a propionyloxy group.
When each of Z and Z1 in formulas [II-1] to [II-10] represents an xe2x80x94O(Cxe2x95x90O)OR1 group, examples of the xe2x80x94O(Cxe2x95x90O)OR1 group include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, and a propoxycarbonyloxy group. When each of Z and Z1 in formulas [II-1] to [II-10] represents an xe2x80x94O(Cxe2x95x90O)SR1 group, examples of the xe2x80x94O(Cxe2x95x90O)SR1 group include a methylthiocarbonyloxy group, an ethylthiocarbonyloxy group, and a propylthiocarbonyloxy group. When each of Z and Z1 in formulas [II-1] to [II-10] represents an xe2x80x94O(Cxe2x95x90O)NR1R2 group, examples of the xe2x80x94O(Cxe2x95x90O)NR1R2 group include an N-methylcarbamoyl group, an N-ethylcarbamoyl group, and an N-dimethylcarbamoyl group. When each of Z and Z1 in formulas [II-1] to [II-10] represents an xe2x80x94O(Cxe2x95x90S)NR1R2 group, examples of the xe2x80x94O(Cxe2x95x90S)NR1R2 group include an N-methylthiocarbamoyl group, an N-ethylthiocarbamoyl group, and an N-dimethylthiocarbamoyl group.
In these formulas, m is preferably 0-2, with 0 being particularly preferred.
The triketone derivative represented by formula [II-1] may be tautomers having the following structures: 
wherein R, X, G, Z1, m and q have the same definitions as described in relation to formula [II-1]. The triketone derivative of the present invention encompasses all these tautomeric compounds and mixtures thereof.
Furthermore, examples of the optionally substituted ring-constituting atoms represented by G1 to G4 in formulas [II-4] to [II-9], which are described as preferable examples of G, include an unsubstituted ring-constituting atom and a ring-constituting atom which has one or two substituents selected from the group consisting of a methyl group, an oxo group, a methoxy group, an isopropyloxy group, and a methoxyimino group. In the above formulas, i is preferably 2.
The process for producing the triketone derivative of the present invention will next be described. First of all, when G in formula [II-11] forms a 5-membered ring including two carbon atoms of the benzene ring adjacent to G, an intermediate for producing the triketone derivative of the present invention, i.e., benzothiophene-2-carboxylic acid, is produced. For example, the intermediate can be effectively produced through the following steps.
(1) First Step 
In the first step, Compounds (a) and (b) are used in an amount of 1 mol each to carry out the above reaction in the presence of 1 mol or more of a base to thereby obtain Compound (c). Either of Compound (a) or Compound (b) may be used in an amount in excess of equimol with respect to the other.
Examples of the base which can be used in the reaction include an alkali metal carbonate, an alkaline earth metal carbonate, and an alkali metal hydroxide. Examples of a solvent which is inert to the reaction and used in the reaction include alcohols such as methanol and ethanol; halohydrocarbons such as chloroform and dichloromethane; hydrocarbons such as hexane and toluene; and water. The reaction is carried out in the temperature range of 0xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of reaction.
Alternatively, the reaction may be carried out in a two-phase system in the presence of a quaternary ammonium salt. Furthermore, Compound (a) may be reacted with sodium hydrogensulfide or potassium hydrogensulfide and chloroacetic acid or bromoacetic acid, to thereby obtain Compound (c).
When the substituent X or Y in Compound (c) is a leaving group, the product may be obtained as a mixture. In this case, the product is purified through a process such as distillation, recrystallization, or chromatographic purification, to thereby yield the target compound.
(2) Second Step 
In the second step, Compound (c) is cyclized to form Compound (d) as shown in the above reaction. The cyclization is carried out in the presence of an acidic reagent in a catalyst amount or in an amount of equimol or more. Examples of preferred acidic reagents include hydrochloric acid, sulfuric acid, phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, polyphosphoric acid, acetic acid, acetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, and sulfuryl chloride. The reaction may be carried out in the absence of a solvent. When a solvent is used, examples of preferred solvents include hexane, dichloromethane, 1,2-dichloroethane chloroform, and N,N-dimethylformamide. The reaction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of the reaction.
Alternatively, Compound (c) is transformed into its acid chloride, and the acid chloride is reacted in the presence of a Lewis acid. In this case, the transformation is carried out by use of a halogenating agent such as oxalyl chloride or thionyl chloride in an amount of equimol or more in the absence of a solvent or in the presence of a solvent such as methylene chloride, 1,2-dichloroethane, or chloroform. The reaction is carried out in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction. The subsequent reaction is carried out by use of a Lewis acid such as aluminum chloride, titanium tetrachloride, or tin tetrachloride. The reaction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of the employed solvent, with stirring until completion of the reaction. When Y of Compound (d) is a hydrogen atom, the other isomer may be intermingled with the product as an impurity. In such a case, the product is purified through a method as described above.
(3) Third Step 
In the third step, Compound (d) is reduced to form Compound (e) as shown in the above reaction. Examples of preferred reducing agents used in the reduction include sodium borohydride and aluminum triisopropoxide. Examples of preferred solvents include methanol, ethanol, water, dichloromethane, and toluene. The reduction is carried out in the temperature range of xe2x88x9220xc2x0 C. to the boiling point of the employed solvent with stirring until completion of the reaction.
(4) Fourth Step 
In the fourth step, Compound (e) is dehydrated to form Compound (f) as shown in the above reaction. The dehydration may be carried out in the presence of a catalyst amount of an acidic substance such as hydrochloric acid, sulfuric acid, or p-toluenesulfonic acid. In this case, a solvent such as benzene or toluene is preferred as a reaction solvent, in that water formed during dehydration can be removed through azeotropic distillation. The formed water is adsorbed in an adsorbent such as a molecular sieve, or is removed through azeotropic distillation with the solvent, to thereby accelerate dehydration. When such an adsorbent is used, the dehydration is carried out in the temperature range of room temperature to 50xc2x0 C., with stirring until completion of the reaction. Azeotropic distillation is carried out through refluxing with heat at the boiling point of the employed solvent by the time a theoretical amount of water is removed.
(5) Fifth Step 
In the fifth step, Compound (f) is oxidized to form Compound (g) as shown in the above reaction. The oxidation is carried out in the presence of an organic peroxide such as hydrogen peroxide or m-chloroperbenzoic acid in an amount of 2 mol or more. In this case, a solvent such as acetic acid or methylene chloride is preferred as a reaction solvent. The oxidation is carried out in the temperature range of xe2x88x9220xc2x0 C. to 100xc2x0 C., with stirring until completion of the reaction.
(6) Sixth Step 
In the sixth step, Compound (g) is hydrogenated to form Compound (h) as shown in the above reaction. The hydrogenation is carried out under similar conditions as employed for customary catalytic hydrogenation. Examples of preferred catalysts include palladium-on-active carbon, Raney nickel, and platinum oxide. In this case, a solvent such as tetrahydrofuran, methanol, ethanol, ethyl acetate, or water is preferred as a reaction solvent. The hydrogenation is carried out in a hydrogen gas atmosphere, with or without pressure, and in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction.
(7) Seventh Step 
In the seventh step, Compound (h) is hydrolyzed to form Compound (i) as shown in the above reaction. The hydrogenation is carried out in the presence of an alkali metal hydroxide in an amount of equimol or more in a mixture of water and alcohol such as ethanol as a solvent. The hydrolysis is carried out in the temperature range of room temperature to the boiling point of the employed solvent, with stirring until completion of the reaction.
The thus-obtained intermediate is used in the following reaction: 
wherein R, X, Y, and m have the same definitions as described in relation to the above-described formulas, to thereby produce triketone derivatives as represented by the above-described formulas wherein Z represents a hydroxy group.
The intermediate carboxylic acid is transformed into an acid halide thereof as described in relation to the above-described cyclization. The thus-formed acid halide is reacted with a diketone in the presence of an organic base such as triethylamine at 0-20xc2x0 C. in an inert organic reaction solvent such as acetonitrile, and the reaction mixture is allowed to react with stirring at room temperature in the presence of a catalyst amount of a cyanide-donor such as acetone cyanohydrin.
When G in the above formulas forms a 6- or 7-membered ring including two carbon atoms of the benzene ring adjacent to G, an intermediate for producing the triketone derivative can be produced through a method described in WO94/04524, WO94/08988, or WO97/03064.
Furthermore, either one of the thus-obtained triketone derivatives represented by the above formulas wherein Z represents a hydroxy group is reacted with a compound which can substitute some or all of the hydroxy groups in accordance with a reaction described, for example, in Japanese Patent Application Laid-Open (kokai) Nos. 62-298563, 62-242755, or 63-2947, to thereby produce substituted triketone derivatives represented by the above formulas wherein Z represents a variety of substituents.
The herbicides of the first and second aspects of the present invention (may be simply referred to as xe2x80x9cthe present inventionxe2x80x9d throughout section III) contain, as an active ingredient, triketone derivatives represented by formulas [I-1] to [I-4] in the first aspect or represented by formulas as described above in the second aspect. The herbicides are produced through mixing the triketone derivative with a liquid carrier such as a solvent or a solid carrier such as a mineral powder, and are prepared into a variety of forms such as water-dispersible powder, emulsion, powder, and granules for use. During preparation of the herbicide, a surfactant is preferably added to the herbicide so as to impart properties such as an emulsifying property, dispersibility, and extendability to the herbicide.
When the herbicide of the present invention is used in the form of water-dispersible powder, the triketone derivative, a solid carrier, and a surfactant are typically mixed, in amounts of 5-55 wt. %, 40-93 wt. %, and 2-5 wt.%, respectively, to thereby prepare a composition, which serves as a herbicide.
When the herbicide of the present invention is used in the form of emulsion, the triketone derivative, a solvent, and a surfactant are typically mixed in amounts of 10-50 wt. %, 35-85 wt. %, and 5-15 wt. %, respectively, to thereby prepare a composition, which serves as a herbicide.
When the herbicide of the present invention is used in the form of powder, the triketone derivative, a solid carrier, and a surfactant are typically mixed in amounts of 1-15 wt. %, 80-97 wt. %, and 2-5 wt. %, respectively, to thereby prepare a composition, which serves as a herbicide.
When the herbicide of the present invention is used in the form of granules, the triketone derivative, a solid carrier, and a surfactant are typically admixed in amounts of 1-15 wt. %, 80-97 wt. %, and 2-5 wt. %, respectively, to thereby prepare a composition, which serves as a herbicide.
Examples of preferred solid carriers include oxides such as diatomaceous earth and slaked lime; phosphates such as apatite; sulfates such as gypsum; and mineral micropowders such as talc, pyrophyllite, clay, kaolin, bentonite, acidic terra alba, white carbon, quartz powder, and silica stone powder.
Examples of preferred organic solvents include aromatic hydrocarbons such as benzene, toluene, and xylene; chlorohydrocarbons such as o-chlorotoluene, trichloroethane, and trichloroethylnene; alcohols such as cyclohexanol, amyl alcohol, and ethylene glycol; ketones such as isophorone, cyclohexanone, and cyclohexenyl-cyclohexanone; ethers such as butyl cellosolve, diethyl ether, and methyl ethyl ether; esters such as isopropyl acetate, benzyl acetate, and methyl phthalate; amides such as dimethylformamide; and mixtures thereof.
Examples of the surfactant which can be used in the invention include anionic, nonionic, cationic, and ampholytic surfactants such as amino acid-type and betaine-type surfactants.
To the herbicide of the present invention, an ingredient having a weed-controlling activity may optionally be added other than the triketone derivative represented by formulas [I-1) to [II-10). Examples of the compound contained in such an ingredient include diphenyl ether, triazine, urea, carbamate, thiocarbamate, acid anilide, pyrazole, phosphoric acid, sulfonylurea, and oxadiazone. These ingredients may appropriately be used in combination.
Furthermore, additives such as a pesticide, a bactericide, a plant-growth-regulator, and a fertilizer may optionally be incorporated into the herbicide of the present invention.
The herbicide of the present invention is applied directly to a weed or to a field where the weed grows, before or after germination of the weed. The manner of application depends on the type of a cultivated plant or the environment of use, and a form of application such as spraying, sprinkling, water sprinkling, or injecting may be employed.
Examples of the cultivated plant to which the herbicide is applied include graminaceous plants such as rice, wheat, barley, corn, oat, and sorghum; broad-leaved crops such as soybean, cotton, beet, sunflower, and rape; fruit trees; vegetables such as fruit, root, and leaf vegetables; and turf grass.
Examples of paddy weeds to which the herbicide of the present invention applies include Alismataceae such as Alisma canaliculatum, Sagittaria trifolia, and Sagittaria pygmaea; Cyperaceae such as Cyperus difformis, Cyperus serotinus, Scirpus juncoides, and Eleocharis kuroguwai; Scrothulariaceae such as Lindernia pyxidaria; Pontenderiaceae such as Monochoria vaginalis; Potamogetonaceae such as Potamogeton distinctus; Lythraceae such as Rotala indica; and Gramineae such as Echinochloa crus-galli. 
Examples of field weeds include broad-leaved weeds, graminaceous weeds, and cyperaceous weeds. Specific examples of broad-leaved weeds include Solanaceae such as Solanum nigrum and Datura stramonium; Malvaceae such as Abutilon theophrasti and Sida spinosa; Convolulaceae such as Ipomoea purpurea; Amaranthaceae such asAmaranthus lividus; Compositae such as Xanthium strumarium, Ambrosia artemisifolia, Galinsoga ciliata, Cirsium arvense, Senecio Vulgaris, and Erigeron annus; Brassicaceae such as Rorippa indica, Sinapis arvensis, and Capsella bursa-pastoris; Polygonaceae such as Polygonum bulumei and Polygonum convolvulus; Portulacaceae such as Portulaca oleracea; Chenopodiaceae such as Chenopodium alubum, Chenopodium ficiolium, and Kochia scoparia; Caryophyllaceae such as Stellaria media; Scrophulariaceae such as Veronica persica; Commelinaceae such as Commelina communis; Euphorbiaceae such as Lamium amplexicaule, Euphorbia supina, and Euphorbia maculata; Rubiaceae such as Galium spurium, Galium aparine, and Rubia akane; Vilaceae such as Viola arvensis; and Leguminosae such as Sesbania exaltata and Cassia obtusifolia. Specific examples of Graminaceous weeds include Sorghum bicolor, Panicum dichotomiflorum, Sorghum haepense, Echinochloa crus-galli, Digitaria adscendes, Avena fatua, Eleusine indica, Setaria viridis, and Alopecurus aequalis. Specific examples of Cyperaceous weeds include Cyperus rotundus and Cyperus esculentus.